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n!"? '' \ JOURNAL OF MYCOLOGY. ! uI'Tim. 





Effik a. Southwokth. David G. Faikchild. Ekwin F. Smith. 



FEBBVART l-J, 1888. 

By Dr. Oskar Bbefeld, 

Full Professor of Botany in Miinster i. W. 

[Translated from Nachridhten aus dem Kluh der Landwirthe eu Berlin, No8. 220-222, by 

Erwin F. Smith.] 

Gentlemen: About four years ago, in January, 1884,1 found op- 
portunity in this place to report the new researches which I bad com- 
pleted upon the smut fungi, the Ustilaginew. To this first communica- 
tion I will today add a continuation explaining the results which I 
have obtained since my last address. 

In nature the smut fungi live as parasites, in a multitude of forms. 
We find them universally distributed on the most dissimilar plants, 
but most frequently upon our cultivated plants and among these, es- 
pecially, upon the different cereals. The usually striking and ruinous 
destructions which they produce in the host plants, and especially in 
the fruit-bearing jwrtion, the spikes and panicles of grain, have been 
known and feared by farmers for a long time, under the name of smut 
diseases, or the phenomena of grain smut. The grain smuts belong 
without doubt to those i)lant diseases which operate most destructively, 
in that they destroy the chief aim of cultivation, the grain itself. For 
this reason first of all they have a very just claim to the most exact 
research for their recognition and prevention. 

As a matter of fact, researches on the smut fungi and observations 
and experiments on the appearance and prevention of smut diseases 
have been made repeatedly for a long time and have often claimed 
221C1— No. 1 1 1 

attention. Keeping step with furtlier knowledge and experience in 
mycology they are always taken up afresh whenever any new sugges- 
tions or new views for further enlightenment open up, and whenever 
new methods of I'esearch show new points for attack. 

In this way, then, my researches on the smut fungi and diseases, 
begun about eight years ago, were only the natural continuation of the 
labors of earlier authors ; except that they were accompanied by other 
and fresh tlioughts and supported by methodical expedients such as 
previously had not found emi)loyment, nor, indeed, could find it. They 
were begun after a long stand-still in observations on smut fungi and 
smut diseases, and when renewed experiments with the worn-out 
thoughts and methods would give no new and substantial results. 

Till my experiments everybody proceeded upon the supposition that 
the fungi existing parasitically in nature found their natural conditions 
of existence only upon their hosts, and therefore that the different smut 
fungi could live and grow only upon the different but definite and re- 
stricted host plants, on which they were observed in the open air. Ac- 
cordingly it was very evident that experiments and observations must 
be confined to the host plants; that in order to investigate the connec- 
tion of fungus and disease, the fungous germs, found on the host plants, 
consequently the smut spores, must be sowed again upon the host plants 
and their development followed. The idea was so simple and natural 
that candid minds did not suspect the confusion of perception and judg- 
ment which this thought naturally carried with it. 

Upon the host plants the smut spores find, first, only moisture for 
their development, consequently they must germinate on the surface of 
the plants just as they germinate in a small drop of water. Now, ger- 
mination experiments with smut spores in water have shown most 
convincinglj^ that the spores in many cases, e. g., in corn smut, do not 
germinate; that in other cases they germinate only in small numbers 
and very imperfectly, e. (j., in oat smut and millet smut. From these 
negative or at least imperfect results of germination in water, which 
results were to be observed in just the same way upon the surface of 
the host plants, the universal distribution of the fungi in question and 
of the smut diseases in grain could be exi)lained only very imperfectly 
or not at all. Nevertheless, these explanations gave satisfaction, the 
rudimentary consistency of facts was regarded as complete, and to no 
mycologist did it occur that any one would succeed in acquiring new 
information or in making a very important advance iu the knowledge 
of smut diseases. 

My culture methods for the investigation of fungi, were slowly and 
painfully established and brought to gradual completion during the 
long period of more than sixteen years, and meanwhile put to use, alike 
in the minute schizomycetes and the great mushrooms, iu the simplest 
as well as the most highly developed fungous forms, with similar trench- 
ant results for knowledge of the developmental history of fungi. These 

led me, in their further perfectiou, gradually to results which made the 
differeace betweeu fungous forms that maintain themselves as parasites 
on living plants and animals, and such as live only as saprophytes on 
dead organic substances, appear less sharp than, according to the com- 
mon state in nature, it was believed to be. I succeeded artificially, 
with my nutrient solutions, in growing fungous forms as luxuriant as 
were to be observed in nature on the host plants, and in some cases 
much more luxuriant, e. g., Peziza ciborioules and P. sderotiomm, which 
in nature are found living on clover and rape; also, Sphacelia se- 
getum, the fungus of ergot, and many others. This itself led me to 
considerations on the nature and reality of parasitism and on the loay 
in tvhich the various parasitic phenomena in nature might come about. 
These observations always led only to the one reasonable conclusion, 
that parasitism can be nothing else than a form of existence which has become 
more or less suited to the fungus according to the length of time, and differ- 
ently and specifically adapted to it in each individual case, but which, for 
all that, has become by no means constant. It was only the natural con- 
sequence of these trains of thought, based upon observations in nature, 
and upon the results obtained in my culture experiments, to draw this 
conclusion: Even in the most distinctly marked cases of parasitism, in 
tchich the fungus is found only on given plants or even on particular por- 
tions of these, nothing else is before us except the furthest extended phenom- 
ena of the same adaptation, which by its more developed form produces 
the OUTWARD APPEARANCE, as though the natural conditions for the ex- 
istence of these parasites were given exclusively in the living substratum, 
consequently in the particular host plants, or special portions of these, and 
as though every other way of life and growth were altogether excluded. 

And by this outward appearance all mycologists were obviously cap- 
tivated, until my investigations, l^o botanist had thought of critically 
examining the essential nature of parasitism, of following out naturally 
the sole possible origin of parasitic phenomena, and of making it clear 
in what way the whole multitude of its variations is simply and natur- 
ally subordinate to one unifying thouglit, a thought which included in it- 
self not only the possibility but also the probability that fungi living par asit- 
ically — at least the greater part, if not all of them — can live outside of the 
host plant. 

When, almost ten years ago, I gave publicity to my views on parasitism 
along with my culture methods, and at the same time expressed strong 
confidence that unquestionably it must be possible artificially to culti- 
vate most, if not all, parasitic fungi, my views remained not only gen- 
erally unconsidered, but were in special cases, m the BotanischeZeitung, 
even scornfully criticised. This circumstance shows, as no other, the 
confused judgment of mycologists upon parasites and parasitism, and 
enables one to measure clearly the difference between the old sterile 
ideas and the new fruitful thoughts. Only this confusion of ideas, 
which must be plain upon considerate reflection, could have prevented 

the earlier mycologists from at once striking into the broader way for the 
investigation of parasites, the method of cultivation in artificial nutrient 
solutions instead of in mere loaler. 

As great as the fundamental difference in ways of thinking and meth- 
ods which separates the earlier and the present investigations, so great 
is the difference in the results obtained, as I shall now show more ex- 
plicitly in further experiments with the smut fungi. 

Even iu my first address on smut fungi and smut diseases, in 1884, 1 
communicated important and unexpected results which I had then 
reached in cultivating different smut spores in artificial nutrient solu- 
tions.* While in mere water the smut spores either did not germinate, 
e. g.f the spores of corn smut, or germinated only scantily and con- 
cluded their development with the formation of a short germ tube 
(promycelium) and a few germ cells (conidia or sporidia); the same 
spores germinated in nutrient solutions without exception, the germ 
tubes produced conidia in inexhaustible abundance,t which only grew 
out into germ tubes when the nutrient solution was exhausted. The 
conidia were of definite shape and size, therefore specific for the indi- 
vidual forms of the smut fungi. In a number of forms they were pro- 
duced under liquid, e. g., in JJstilago carbo, V. cruenta, U. maydis, 
which are known as oat, millet, and corn smut ; in other forms they were 
produced above the liquid in the air, e. g., in the stone smut of wheat, 
Tilletia caries. In this fungus and the forms related to it there grew 
further in nutrient solutions, out of the conidia derived from spore germi- 
nation, large, richly branched mycelia, which again produced the same 
conidia iu uulimited abundance as short lateral shoots ; there arose, in 
fact, mold-like turfs, which were again produced out of the new-formed 
and again new-sowed conidia, always in the same manner and abund- 
ance, so long as the culture was maintained in the nutrient solution. 
In oat, millet, and corn smut, and forms closely related to these, the fur- 
ther development of the conidia produced by spore germination under 
the nutrient solution continues not mold-like, but quite otherwise. The 
conidia of definite size and shape produced on the short germ tubes of the 
smut spores multiplied in just this size and shape by direct sprouting at 
definite places, and that always at both ends, in a rapid manner, without 

Furthermore, the s[)rout-colouie8 of conidia which were so produced, 

* Additional cultures with parasites selected at random resulted in showing that in 
almost all cases maintenance outside of the host plant is easy to accomplish ; even the 
lichen forming Ascomycetea, which live on and with different algse, representing the so- 
called lichens of nature, could he easily cultivated " without algse" in my nutrient 
solutions with the help of my culture methods, as final valid proof that lichens are 
nothing but a number of Ascomycutes which live parasitically on different algae. Vide 
Moller, Kullur fleclitenhildender Ascomyceten ohne Algen. Arbeitenansdembotanischen 
Institute in Miinster i. W., 1887. 

t For those who only read my address and have not seen the accompanying illustra- 
tions on the wall charts, I refer to the tables in my book Brandpilze I. 

and which easily separated into their individual members, enabled us 
to recognize in the different forms of smut fungi, to which they belong 
as stages of the development, a different but always definite and typ- 
ical appearance, depending on the form and size of their conidia. Thus, 
for example, the sprout conidia in oat smut (Flugirand) were produced 
from the long egg-form conidia of this smut; the sprout colonies of the 
corn smut were made up of the longer somewhat spindle-form conidia, 
peculiar to this smut fungus; the sprout aggregations of the millet 
smut had the narrow spindle form of the conidia of this fungus. Even 
in the different species of the smut genus Ustilago, investigated four 
years ago, there were found "as characteristic stages of the develop- 
ment," just as many specific and different sprout forms as are found 
round to elongate conidia of the various sizes. 

In their appearance and in their growth hy sprouting these aggregations 
of conidia in the smut fungi are also similar to the large number of those 
long-lcnown fungous forms which, from their clmracteristic growth and in- 
crease hy so called sprouting, it has been thought necessary to consider as 
specific forms, and also to specially distinguish as SPBOUTlNa FUNGI. 
They also show themselves fully consonant with the previously known 
sprout fungi in that, like them, they continued sprouting indefinitely, so 
long as they vegetated in congenial nutrient solutions ; and in that they 
always remained in sprout form, consequently staid sprouting fungi, 
and passed over into no other form, only at most, not always, pushed 
out into germ tubes, when the nutrient solutions were exhausted. The 
sole difference, a negative one, however, between the newly discovered 
sprout forms of the various smut fungi and the fungus forms previously 
passing current as "sprout fungi" par excellence, which forms we en- 
counter so very frequently in our nu trient solutions, and designate briefly 
as "mold (Kahm) fungi," or "yeast fungi," could be expressed only as 
follows: We now know the yeast or conidia-sprouts of the smut fungi 
not simply by their endlessly continued sprouting in nutrient solutions; 
we know further through the first beginnings of the culture, the sowed 
smut spores, that they represent nothing but special stages of develop- 
ment of the various smut fungi from which they were evolved; so far we 
do not know this of the other sprout fungi, because they have not yet 
been investigated from the right points of departure. From this it fol- 
lows, further, that we do not judge correctly when we hold the so-called 
sprout fungi for independent fungi, as has been done hitherto, upon the 
fact alone of their endless sprouting in nutrient solutions. From the 
definite form of their individual members and the definite places of 
sprouting these must rather pass for nothing else than simple conidia 
sprouts of other fungi, consequently for stages in the development of 
higher fungous forms, which when sprouting in nutrient solutions behave 
like independent fungi, in just the same way as do the sprout-conidia 
of the smut fungi. Artificial culture of the different smut fungi in nutri- 
ent solutions brought along then in its train as a side issue the obvious solu- 

tion of another still open question, the sprout-fungus or yeast question. It 
could only be coiisideied as a simple matter of time when, through the 
spore culture of the remaining higher fungi, further and supplementary 
proof would be brought as to which forms among these fungi include 
in their course of development the still remaining sprout fungi which 
do not belong to the various smut fungi. The investigations in this 
direction have meanwhile, it may be mentioned in passing, already led 
to the most far-reaching results in the most diverse Asco mycetes and 

Aside now from the forms of smut fungi which, like Tilletia, produce 
large mycelia with conidiain nutrient solutions, and aside further from 
the forms which, like Ustilago carbo, U. cruenta, and U. maydis, pro- 
duce oouidia in endless sprouting in yeast form, there are still other 
forms ichich produce conidia on the conidiophores of the germinating smut 
spores (the promycelia), which do not sprout directly, hut always first groto 
out again into new promycelia until the conidia sprouting begins anew on 
these. Here belong, for example, Ustilago longissima on Poa aquatica, 
and U. grandis on Phragmites communis, with many-celled promycelia, 
and U. bromivora on Bromus secalinus, with typical two-celled promy- 

Finally, forms were also discovered, as for example Ustilago Grameri 
on Setaria, U. hypodytes ou Elymus arenarius, etc., the s7Hut spores of 
which, germinating in nutrient solutions, produce no conidia, but only sterile 
germ tubes, that grow into richly-branched mycelia, tchich in turn also re- 
main free from conidia. Here afterward the single threads pushed 
far out, stolon-like, and abjointing, constituted, in place of the absent 
conidia, the richly increased mass of germs present in the nutrient solu- 

In short, these are the most essential results which the cultivation of 
the spores of the various smut fungi in artificial substrata, in nutrient 
solutions (therefore outside of the host plants, where they are found in 
nature) had given four years ago. The number of forms the cultivation 
of which was tried in nutrient solutions then amounted to more than 
twenty. As supplementary, I have extended the cultivation to an ad- 
ditional twenty forms, some of which brought to light similar peculiari- 
ties as in the first series, e. g., in the genera Schizonella and Tolypospo- 
riuni, which produce sprout-conidia ; while others yielded new and sup- 
plementary facts, the special communication of which however, • as well 

* Only incidentally I will state for example that the genns Neovossia and species of 
Urocyalh behaved the same as Tilletia. Of the recently investigated forms of the old 
genua Ustilaflo, which in its present extent is wholly untenable, a number behaved 
the same as Ustilago cnrbo, and produced sprout-conidia of various shapes ; others, 
e. a., U. caricis, U. siihincliiw, and U. echinata, germinated in a specific manner with 
the production of little conidiophores bearing air conidia similar to Peronospora. Us- 
tilago VaiVaniii agreed with the type of U. longissima; TJ. hordei, a recently distin- 
guished form on Hoj-rfeaceic, produced large, sterile, e. (/., conidia-free, mycelia, like U. 
Crameri, etc. 

as the conclusion I have reached as to the morphological value of smut 
spores and as to the natural position of the smut fungi in the system of 
fungi, will be omitted here because they possess a strictly botanical sci- 
entific value, but do not directly contribute to the understanding of smut 
diseases, and their propagation, subjects now specially in question. 

From the ease and luxuriance with which these cultivated parasites, 
vegetated and fructified in the nutrient solutions, with most abundant 
increase of their germ cells in just the same way as any other fungous 
forms occurring in nature as saprophytes, the conclusion followed 
almost of itself that smut fungi can also vegetat« in nature on dead 
substrata lilie all other saproiihytes, and that, although invisible to 
the naked eye, they here run through just the same forms as were found 
in the nutrient solutions and have just been described. This conclusion 
found still further support in the fact that I had used as nutrient solu- 
tions and nutrient substrata for the smut fungi the entire series of 
media, the composition and compounding of which I had given in detail 
in my Culture Methods for the Investigation of Fungi and had ascertained 
as suitable for the cultivation of saj)rophytic fungi, especially extracts 
from the fresh dung of our domestic animals, in which the development 
of the smut fungi took place with the same ease as all other saprophy- 
tes which were cultivated therein. The widespread occurrence of the 
most various yeast conidia in the dung of herbivorous animals, conidia 
which are in no way different from those of the investigated smut fungi, 
was in accord with this conclusion, and further experiments by sowing 
smut spores in fresh dung not too wet proved directly the increase of 
the germs in the fresh dung substances of the earth. Finally, the long 
known and uniform statements of husbandmen that their grain was 
especially subject to smut when they had impregnated the field with 
fresh dung found its equally simple and natural explanation in the now 
actually established increase of smut germs in the fresh dung. 

Instead of smut spores almost incapable of germination in water, e. 
g., corn smut; instead of only scattering and rudimentary spore germina- 
tions in mere water, e. g., oat smut, from the activity of which, according 
to the knowledge of the time, the occurrence of smut and the spread 
of smut diseases could only be derived, there was now brought to light 
through the new discoveries and their consequences, an entirely new 
and rich vegetative condition of smut fungi. This made the question 
not one of exclusive parasites and their exclusive development on 
the host plants, but revealed, as it were, a most productive center of in- 
fection, outside of the host plants, for the propagation of smut diseases; 
a center of infection in which are operative not the few weak germs of 
water germination but an abundance of conidia capable of vigorous 
germination — conidia which can grow out easily into long germ-tubes 
and reach and attack the host plants. 

However extremely probable or wholly self-evident it may now seem 
to have been from the beginning that germs of smut fungi, developed 


in nutrient substrata of all sorts, might actually produce the smut 
diseases in the host plants; however convincing the experience of hus- 
bandmen on the relations of fresh dung to the appearance of smut 
diseases in grain, — the described results of artificial cultivation being 
also consonant — these alone do not amount to conclusive proof, but 
remain probabilities with which we can not be satisfied. The new 
investigations of smut fungi, which began with the cultivation of the 
parasites outside of the liost plants and which with the results here attained 
are half exhausted, will not be conclusive and exhaustive for the (eti- 
ology of smut diseases until the supplementary half is appended, until 
through various and rationally conducted infection experiments it is actually 
shown in what way and under what circumstances the richly multiplied 
germs living saprophytically outside of the host plants attach the latter and 
produce the smut diseases, how and in what places the germs penetrate into 
the liost plants, and how within these, widely diverging from the transfor- 
mations outside of the host plants, they are changed into smut spores. 

And now, for these infection experiments, the easy maintenance of 
smut fungi in any sort of nutrient solution and the subsequent end- 
less increase of their germs, oifered an inexhaustable source for the 
production, at will, of an infective material no less fresh and vigor- 
ous than capable of attack — a material, immediatelj' and easily availa- 
ble in all possible variations, never before used, and admirably adapted 
for the artificial production of smut diseases in the host plants. 

(To he continued.) 



A. A. CeoZIER. 

The influence of various chemicals upon the germination of seeds is 
but little understood. Many which have a fertilizing effect when ap- 
plied in small amounts to the growing plant are injurious when a strong 
solution is applied to the seed. There is evidence, on the other hand, 
that many substances when applied to the seed will hasten germination 
and increase the vigor of the young plants. An account of some of 
these is given by Prof. L. H. Bailey, in Bulletin 31 of the Michigan Ag- 
ricultural College. 

The following experiments were made with blue vitriol and copperas 
at the Iowa Experiment Station in 1889 : 

First, a rough test was made with a strong solution of blue vitriol, a 
teaspooufulin half a saucer of water. Corn was soaked in this twenty- 
four hours, and another lot soaked in pure water the same length of 
time, and both lots planted in soil in the greenhouse May 11. Exami- 
nation was made daily with the following results, the figures showing